1. Field of the Invention
The present invention relates to a camera using a variable magnification photographic optical system, and more particularly, to an improvement in an interlocking relationship between the variable magnification photographic optical system and another optical device.
2. Description of the Related Art
A conventional zoom lens provided camera, as disclosed in Japanese Patent Laid-Open No. 2030/1988, is arranged in such a manner that a gear portion is provided for a zoom ring, rotation power around an optical axis is transmitted through the gear portion to a cam board that moves an electric flash unit and a finder, a sideways movement of the cam board moves a light emitting portion of the electric flash unit and a lens of the finder.
A conventional camera of this type, wherein the driving power for the electric flash unit and the finder is obtained from the cam ring rotating around the optical axis, must have a means for rotating the cam ring on the body, i.e. the fixed side. Thus, there is the disadvantage that the body side becomes short of space. Further, because of the arrangement restriction that the ring at the outermost portion of a lens barrel transmits the driving power to the electric flash unit and the finder and that a partial protrusion of the gear mechanism for transmitting the above-described driving power is necessary, the conventional camera has the disadvantages of requiring a complicated light-shield for the lens barrel as well as a space for accommodating the light shield.
In addition, owing to such mechanical restrictions, the sliding amount between a cam, integrated with a cam ring, for an electric flash unit and an interlocking member, which is disclosed in Japanese Patent Laid-Open No. 50324/79 and Japanese Utility Model Laid-Open No. 48933/90, and the sliding amount between a cam board of an electric flash unit and a flash unit member, which is disclosed in Japanese patent No. 2030/88, become large relative to the moving stroke action, so that these cams wear out quickly. Further, driving a finder lens through a large amount of cam sliding results in the finder lens being susceptible to vibration under the influence of friction of the cam, thus leading to an image vibration in the finder, etc. In order to prevent this problem, it is necessary to improve the precision of the mechanism, etc., thus resulting in deterioration of both the cost and space aspects of the conventional camera.
In particular, speed reduction and connection by means of a large number of gears, such as is disclosed in Japanese Patent Laid-Open No. 2030/1988, causes the number of components to increase, the mechanism to be complicated, and the positioning operation, etc., to be aggravated, resulting in degraded assembly characteristics.